Background and aims
The aim of this study was to test the effect of Azospirillum brasilense on the superoxide anion production (O2 •−) and enzymes related with redox metabolism in roots of wheat (Triticum aestivum).
Methods
A. brasilense Sp245 and T. aestivum seeds cv Nana F2007 were used in this study. Wheat roots were stained with nitro blue tetrazolium (NBT) to visualize and localize O2 •− production. Superoxide dismutase (SOD) and peroxidase (POX) activities were assayed in native PAGE.
Results
We found that A. brasilense application resulted in a decrease in meristem length and cell size, and in a reduction in the O2 •− level in roots. The bacteria stimulated SOD and soluble POX isoenzymes, particularly in the zone of the root tip. Qualitative O2 •− production in roots treated with LaCl3, a Ca2+ channel blocker, in combination with A. brasilense was comparable to inoculated roots. Similar results were observed with the Ca2+ ionophore A23187.
Conclusions
Our results suggest that O2 •− metabolism is important during the interaction of wheat and A. brasilense, and that the antioxidative enzymes such as SOD and POX are involved in its regulation.